Engineered VP1 mRNA Vaccine Induces Immunity and Complete Protection Against Feline Calicivirus in Cats.

Area of Science:

• Veterinary Medicine
• Immunology
• Molecular Biology

Background:

• Feline calicivirus (FCV) is a primary cause of upper respiratory infections in cats.
• Traditional vaccines exist, but messenger RNA (mRNA) vaccines offer advantages like rapid development and cost-efficiency.
• Developing effective FCV vaccines is crucial for feline health.

Purpose of the Study:

• To develop and evaluate a novel mRNA vaccine against FCV using a modified VP1 protein.
• To assess the immunogenicity and protective efficacy of the LNP-VP1-mRNA vaccine in feline models.

Main Methods:

• Constructed a codon-optimized VP1 gene with a specific amino acid deletion for immunogenicity.
• Generated VP1-mRNA via in vitro transcription and encapsulated it into lipid nanoparticles (LNPs).
• Administered the LNP-VP1-mRNA vaccine via prime-boost immunization in mice and cats, followed by FCV challenge.

Main Results:

• Confirmed successful FCV-VP1 expression in cells and characterized the LNP vaccine formulation.
• Vaccination induced dose-dependent anti-FCV IgG and neutralizing antibodies, along with key cytokine responses (IFN-β, IFN-γ, IL-4, IL-6).
• Achieved 100% survival and complete protection against FCV challenge in vaccinated cats, with no clinical signs.

Conclusions:

• The LNP-VP1-mRNA vaccine is a safe and highly effective candidate for preventing FCV infection in cats.
• This mRNA vaccine platform shows significant promise for controlling feline respiratory diseases.
• Further development could lead to a new generation of FCV vaccines.